Synthesis,Structural Characterization and Hydrogen Storage of Nickel-containing Mesoporous MCM-48 by Electroless Plating

Hydrogen is a promising fuel for it is clean,highly abundant and non-toxic,but on-board storage of hydrogen is still a challenge.So it is imperative to have an efficient method of hydrogen storage.The mesoporous MCM-48 especially the nickel-containing MCM-48 has great potential in hydrogen storage.MCM-48 was prepared by hydrothermal synthesis.Then electroless plating technology was used to deposit Ni on the surface of MCM-48 under ultrasonic environment.Powder X-ray diffraction（XRD）,transmission electron microscopy（TEM）,and N2 adsorption-desorption were employed to investigate the pore structure properties.The results showed that all the samples had Ia3 d cubic structure and pore channels were highly ordered.Hydrogen adsorption studies showed that the MCM-48 after nickel plating adsorbed nearly twice the amount of hydrogen than pure MCM-48 at 2.0 MPa,263 K.So we believe that a small amount of Ni can improve the capacity of hydrogen adsorption of MCM-48 efficiently.

Continuous Surface Metallization of Polyimide Fibers for Textile‑Substrate Electromagnetic Shielding Applications

Despite tremendous effort,continuous fabrication of high-performance conductive polymer fibers for electromagnetic interference(EMI)shielding applications remains a daunting technical challenge.In the current study,we report an efficient strategy for continuous surface metallization of polyimide fibers used in textile-substrate electromagnetic shielding applications.Polyimide fibers with pendent carboxyl groups(PIC)were first fabricated,and a conductive nickel layer was continuously coated on the PIC surface by electroless metal deposition(ELD).The carboxyl groups introduced onto the fiber surface acted as binding sites for the Ni^(2+)ions,and the complexation reactions greatly increased the Ni^(2+)adsorption capacity and efficiency of the PIC fibers during the ELD process and ensured continuous fabrication.Through judicious control of the plating time,a series of nickel-layer-coated PIC fibers(Ni-PIC)were constructed with Ni loadings ranging from 20 to 230 wt%.The resultant Ni-PIC fiber containing 65 wt%Ni exhibited conductivity of 223 S cm^(−1),and the corresponding fabric exhibited an EMI shielding effectiveness(EMI SE)of 44 dB in the X-band.The corresponding EMI SE was further improved to 83 dB after the fiber was treated at 300℃ for 1 h because of the crystallization of the Ni layer.The prepared Ni-PIC fibers and fabrics were also used in pressure sensors and electrothermal conversion,which demonstrated outstanding adaptabilities to various temperatures and mechanical properties.Overall,this work provides an efficient route for developing high-performance conductive polyimide fibers for EMI shielding applications,especially for use in military and aerospace equipment and in other harsh environments.